The present invention relates to compositions for the treatment of diseases of the gastrointestinal tract. More particularly, the present invention relates to compositions for the oral delivery of corticosteroids.
Oral corticosteroids are used in the treatment of inflammatory diseases of the gastrointestinal tract, such as Crohn's disease and ulcerative colitis where they act principally topically to suppress the inflammatory response. The use of oral corticosteroids for the treatment of glomerulonephritis via local intestinal action has also been described (U.S. Pat. No. 6,239,120).
Corticosteroids can cause undesirable side-effects if there is long-term systemic exposure, such as Cushings syndrome and osteoporosis. Therefore, corticosteroids are currently typically used to treat the acute symptoms of the diseases mentioned above but are not generally used for long-term treatment.
It is desirable to minimise systemic exposure to corticosteroids. One approach is to use rectal dosage forms such as suppositories and enemas which are effective at delivering drug into the distal regions of the colon. Oral formulations which provide targeted drug delivery to the small intestine and colon have also been devised. These typically comprise tablets or pellets which are coated to prevent drug release in the upper regions of the gastrointestinal tract. Coatings described for this purpose include enteric (gastroresistant) materials which are insoluble in stomach acid and dissolve in intestinal fluid. Materials which are biodegraded by the microflora residing in the colon have also been described, such as in U.S. Pat. No. 6,534,549.
The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.